councilman vs council member

councilman and council member both are nouns.

Word	Noun	Adjective	Verb	Adverb
councilman	Yes	No	No	No
council member	Yes	No	No	No

As nouns, council member is a hypernym of councilman; that is, council member is a word with a broader meaning than councilman:

Other hypernyms of councilman include councillor, adult male, man.

councilman (noun)	council member (noun)
a man who is a council member	a member of a council